I don't know what the plan is. It seems like it would make sense to transition to B-29s, due to the distances involved and existing air base infrastructure. Doolittle would be the guy to supervise such a move. What a remarkable man he was. But they better get moving. It could take a few months for training and transport to the Pacific. I don't expect they will see action much earlier than the end of August.
According to wiki they were based in Okinawa but did not get B-29s until after the surrender, actually got the firt B29 the day after Hiroshima:
Pacific Theater
Following the end of the war in Europe in May 1945 plans were made to transfer some of the B-17/B-24 heavy bomber groups of Eighth Air Force to the Pacific Theater of Operations and upgrade them to B-29 Superfortress Very Heavy (VH) bomb groups. As part of this plan, Eighth Air Force headquarters was reassigned to Sakugawa (Kadena Airfield), Okinawa, on 16 July 1945, being assigned to the United States Strategic Air Forces in the Pacific without personnel or equipment.
On Okinawa, Eighth Air Force derived its headquarters personnel from the inactivated XX Bomber Command, and Lieutenant General James H. Doolittle assumed command, being reassigned from England on 19 July. The command controlled three airfields on Okinawa, Bolo, Futema, and Kadena Airfield. The Eighth received its first B-29 Superfortress on 8 August 1945.
On one hand it would make sense to bring the 8th Air Force over as currently organized. The 8th being based on Okinawa could continue with the B-17/B-24 wings and carry max bomb load of roughly 10,000 pounds.
The advantage to using the B-17/B-24 you already have an air force in being, minimal training required to get started on the reduction of Japan.
The B-29 gives you double the bomb load with a better defensive gun arrangement than the B-17/B-24. However by going to the B-29 you would need at least a 3 to 6 month training cycle to get the Bombardment groups up to speed, IMHO.
I am not sure what was in the training pipeline regards the B-29 back in the States so the Mighty 8th may have been able to deploy faster. The fact that in August the 8th was still getting up to speed may indicate otherwise.
Regards
alfa6 ;>}